Device for imparting false twists on a filamentary yarn

ABSTRACT

In a false twisting device provided with a false twisting spindle rotatably held by holding rollers, the rotation speed of the false twisting spindle is selectively changed to either a normal running speed or a slower speed, which is necessary for carrying out the threading up operation, by means for selectively changing the contact of a part of a driven system with a frictional driving means.

United States Patent [191 Murakami et al.

[ Mar. -18, 1975 DEVICE FOR IMPARTING FALSE TWISTS ON A FILAMENTARY YARN Inventors: Shiro Murakami; Kenzi Kanda; Jiro Nakajyo, all of Matsuyama; Makoto Yamasaki, Iwakuni, all of Japan Assignees: Teijin Limited; Teijin Seiki Co.,

Ltd., both of Osaka, Japan Filed: Mar. 12, 1974 Appl. No.: 450,316

Foreign Application Priority Data Mar. 26, 1973 Japan 48-36915 Nov. 20, 1973 Japan 48-133240 U.S. Cl 57/77.4s, 57/92, 57/93 Int. Cl. D02g 1/04, DOlh 7/92 Field of Search 57/1 R, 34 R,5151.6,

Primary ExaminerDonald E. Watkins ABSTRACT In a false twisting device provided with a false twisting spindle rotatably held by holding rollers, the rotation speed of the false twisting spindle is selectively changed to either a normal running speed or a slower speed, which is necessary for carrying out the threading up operation, by means for selectively changing the contact of a part of a driven system with a frictional driving means.

13 Claims, 12 Drawing Figures PATENTEBHAR 1 81% SH'LEI 3 Bf 6 SUMMARY OF THE INVENTION The present invention relates to an improved device for imparting false twist on a thermoplastic filamentary synthetic yarn, and more particularly relates to a device for imparting false twists, in an apparatus, which is utilized for carrying out a continuous process of drawing an undrawn or incompletely drawn thermoplastic filamentary synthetic yarn, and then imparting false twists to the drawn yarn, or for carrying out the abovementioned drawing process simultaneously with imparting false twists to the yarn being drawn.

It is well known that a so called draw-false twisting apparatus, whereby a process of drawing an undrawn or incompletely drawn thermoplastic filamentary synthetic yarn and the successive process of imparting false twists to the drawn yarn are continuously carried out as combined processes, or the above-mentioned drawing process is carried out simultaneously with the false twisting process, has been developed and utilized as a useful practical apparatus which reduces production costs and manual operations. There are two types of the above-mentioned draw false twisting apparatus. One is the apparatus wherein the undrawn or incompletely drawn thermoplastic filamentary yarn is first drawn between a feed roller and a draw roller, then the false twists are successively imparted to the drawn yarn by a false twisting device and then the false twisted yarn is taken up to a yarn package by a winding means. In the other type of apparatus the above-mentioned drawing and false twisting operations are carried out simultaneously, and then the false twisted yarn is taken up to a yarn package by a winding means. As hereinbefore mentioned the material yarn supplied to the apparatus is an undrawn yarn or incompletely drawn filamentary yarn. When such yarn is supplied to the apparatus, first a yarn end from a supply yarn package is threaded into a false twisting means such as a false twisting spindle, then introduced to a feed roller, a space adjacent to a heater for carrying out heat setting of the yarn, a drawing roller etc., of the apparatus successively, while the yarn is carried into a suction means such as an aspirator. As the yarn is an undrawn or incompletely drawn yarn, if the yarn contacts the heater, for example, if a polyester synthetic undrawn yarn contacts a heater which is maintained at about 200C, the contacting portion of the yarn is broken, so that the abovementioned application of the yarn to the processing elements of the apparatus cannot be carried out. To eliminate the above-mentioned undesirable result, it has been proposed that, at first the false twisting operation should be commenced without bringing the yarn into contact with the heater, and thereafter the yarn passage should be displaced to the side of heater so as to bring the yarn into Contact with the heater. However, we have confirmed in practical mill operations, that the yarn is often broken when the false twisting operation is commenced without first bringing the yarn into contact with the heater, or when the yarn is displaced to the heater after the initial false twist operation.

The principle purpose of the present invention is to eliminate the above-mentioned undesirable result.

Based on repeated tests during actual mill operations, we have found that, if the number of false twists imparted to the yarn when the operation commences is reduced from the number of false twists expected in the normal operation at a predetermined definite ratio, the above-mentioned yarn breakage can be effectively eliminated.

Consequently, we have created an improved mechanism for driving a false twisting spindle to attain the above-mentioned system for changing the driving speed of the false twisting device. That is, in the preferable embodiments of the false twisting device according to the present invention wherein a false twisting spindle is rotatably held by a holding means, the driven part of the spindle or the holding means is provided with multiple cylindrical portions, the diameters of which preferably change in steps along the axis of the driven part of the spindle or holding means. and the driven part of the spindle or the holding means is forced to contact frictional driving means by urging means. In addition the relative contacting position of the driven part of the spindle or the holding means to the frictional driving means is capable of being changed along the axial direction of the spindle or holding means by a displacing means. The displacing means is operated manually.

BRIEF EXPLANATION OF THE DRAWINGS FIG. 1 is a schematic side view of a draw-false twisting apparatus utilizing an improved false twisting device according to the present invention;

FIG. 2 is a schematic plan view of the improved false twisting device shown in FIG. 1;

FIG. 3 is a side sectional view of the false twisting device, taken along a line Ill III in FIG. 2;

FIG. 4A is a schematic diagram showing a part of spring device utilized for the false twisting device shown in FIG. 2;

FIG. 4B is a diagram showing the function of the spring device shown in FIG. 4A;

FIG. 5 is a schematic plan view ofa modified embodiment of the false twisting device according to the present invention;

FIG. 6 is a side sectional view of the false twisting device, taken along a line VI-VI in FIG. 5;

FIG. 7 is a side view of the false twisting device, from right side in FIG. 6;

FIG. 8 is a schematic plan view of another embodiment of the improved false twisting device according to the present invention;

FIG. 9. is a side view, partly in section of the device shown in FIG. 8;

FIG. 10 is a schematic plan view of still another embodiment of the improved false twisting device according to the present invention;

FIG. 11 is a side view, partly in section of the device shown in FIG. 10.

DETAILED ILLUSTRATION OF THE INVENTION Referring to FIG. 1 in a draw-false twisting apparatus, provided with an improved false twisting device according to the present invention, an undrawn yarn l supplied from a yarn package 2 is fed to a feed roller 4 after passing through a yarn guide 3 and the yarn is then stretched in a drawing zone between the feed roller 4 and a drawing roller 8 which is driven at a higher peripheral speed than the feed roller 4, and the false twist is imparted to the yarn 1 by a false twisting device 7 while the yarn 1 is subjected to the above-mentioned drawing operation. During the above-mentioned drawing and false twisting operations, the twists imparted to the yarn between the feed roller 4 and the false twisting device 7 are subjected to a heat setting operation by a heater 5 disposed along the yarn passage between the feed roller 4 and the false twisting device 7, while the above-mentioned twists set by the heat set treatment are untwisted in the downstream yarn passage between the false twisting device 7 and the drawing roller 8. The yarn 1 is then wound on a yarn package 10 by a winding means 9. In the apparatus shown in FIG. 1, a guide pin 6 is displaceably mounted by a bracket (now shown) so as to displace the yarn passage from the heater 5 when it is required to introduce the yarn 1 to the apparatus.

An improved false twisting device 7 utilized in the apparatus shown in FIG. 1 is hereinafter illustrated in detail with referring to FIGS. 2 and 3. In this false twisting device 7, a false twisting spindle 11 comprises a hollow tube member 11a and a laterally expanded portion 11b which is formed at an axially middle portion of the hollow tube member 11a. A head portion lid is formed at a bottom end of the tube member 11a, and a false twist pin 11c is rigidly disposed in the head portion 11d. The top end portion lle of the hollow tube member 11a is also expanded laterally. The false twist spindle 7 is driven by a friction 'drive roller 12 in such a way that the expanded portion 11b of the tube member 11 is urged against the drive roller 12 during threading up operation and a non expanded portion of the tube member 110 of the spindle 11 is urged against the drive roller 12 after a predetermined time after the yarn 1 is introduced into the apparatus. The spindle 11 is turnably held by a pair of holding rollers 13, 14, each provided with a pair of flanges 13a, 13b, 14a, 14b, in such a way that the head portion 11d and the top end portion lle of the tube member 11 respectively fit against the upper and lower edges of the above-mentioned flanges 13a, 14a and 13b, 14b, as shown in FIG. 3. As the holding rollers 13 and 14 have an identical construction, the construction of the roller 13 is hereinafter illustrated in detail. That is, the roller 13 is provided with a bearing assembly disposed therein (not shown) and is rotatably mounted on a shaft 15, which is rigidly mounted on a bracket 16 by a nut 17. A permanent magnet 18 is rigidly held by the bracket 16 so that the false twist spindle 11 is attracted toward the holding rollers 13, 14 and, consequently, the spindle 11 can be stably held at a desirable working position as shown in FIG. 2. At the other end portion of the bracket 16, an upright hollow tube member 16a is formed and a bearing 19 is rigidly inserted into the hollow tube member 16a. The bearing 19 is provided with an upright cylindrical hollow space 19a formed thereinto and a head portion 19b having a small aperture 190. An upright pivot shaft 20 is secured to a supporting bracket 21 which is rigidly mounted on a machine frame 22 by a fastening bolt and nut 23. The upright pivot shaft 20 is inserted into the cylindrical hollow space 19a in such a manner that the bearing 19 is capable of turning about the pivot shaft 20. The pivot shaft 20 is provided with a thinner portion 200 formed at a top half portion thereof which passes through the small aperture 19c of the bearing 19. A compressed helical spring 24 is mounted on the thinner portion 20a of the pivot shaft 20 in the cylindrical hollow space 19a of the bearing 19 and, consequently, the bearing 19 is always urged upward, that is, the bracket 16 is always urged upward. At a top end portion 20a of the upright pivot shaft 20, which projects upward from the small 4 aperture 19c of the bearing 19, a pin shaft 25 is mounted, and a cam plate 26 is turnably mounted on the pin shaft 25 in such a position that the cam surface thereof is always in contact with the top end surface of the bearing 19 as shown in FIG. 3. The cam plate 26 is provided with a handle 27 so as to turn the cam plate 26 about the pin shaft 25. Therefore, when the cam plate 26 is turned about the pin shaft 25 by manual operation, the bracket 16 is displaced upward and downward, that is, the engaging position of the spindle 11 with the friction roller 12 can be changed by the turning motion of the cam plate 26. Consequently, the profile of the cam surface is designed in such a condition that a curved surface 26a is shaped so as to hold the bracket 16 at the position shown by the solid line in FIG. 3 while a plane surface 2611 connected to the curved surface 26a is shaped so as to displace the bracket 16 from the above-mentioned holding position to a position indicated by a dot and dash line. In other words when the curved surface 26a of the cam plate 26 contacts the top end 1% of the bearing 19, as the bracket 16 is forced to turn towards the friction roller 12 by a spring mechanism described hereinafter in detail, the expanded portion 11b of the spindle 11 is urged against the friction roller 12, while when the plane surface 26b contacts the top end 1912 of the bearing 19, the thin portion of the hollow tube member 11a ofthe spindle 11 is urged against the friction roller 12 by the above-mentioned spring mechanism. According to the above-mentioned two contacting conditions of the spindle 11 with the friction roller 12, the spindle 11 can be turned at a lower driving speed or a higher driving speed alternatively. To prevent any distrubance during the displacement of the spindle 11 relatively to the position of the friction roller 12, the peripheral portion 12a of the friction roller 12 is made of an elastic material such as a rubber or plastic material. Further, to avoid any damage of the spindle 11, the peripheral portion of the flanges 13a, 13b and 14a, 14b of the auxiliary rollers 13, and 14 are made of an elastic material such as a rubber or a plastic material In the abovementioned false twisting device, the bracket 16 is always forced to turn about the pivot shaft 20 toward the friction roller 12 during the false twisting operation and, when it is required to separate the spindle 11 from the friction roller 12, the bracket 16 is forced to turn about the pivot shaft 20 toward a direction in which it moves away from the friction roller 12. To attain the above-mentioned turning motion of the bracket 16, the following mechanism is applied to the device, that is, a pin 28 is secured to the bracket 16 as shown in FIG. 3 and a horizontal pin 29 is secured to the supporting bracket 21, a tension spring 30 is held by the pin 28 and the horizontal pin 29 in such a condition that, when the pin 28 is positioned at a position deviated from a line passing through the central axis of the pivot shaft 20 and the connected point of the spring 30 with the horizontal pin 29, the bracket 16 is also turned from the position represented by the above-mentioned line in accordance with the position of the pin 28, and when the pin 28 is positioned at a position on an extension of the above-mentioned line, the working direction of the spring force coincides with the above mentioned line and the spring exerts no turning force against the bracket 16. Referring to FIGS. 4A and 4B, the abovementioned line is represented by a line P -29, and the deviated positions are represented by points P, and P Providing that the P the spring force is represented by F, and the angle between the line 28-29 and the line 20-28 is represented by 0, the force F which urges the bracket 16 toward the friction roller 12 is represented by F sin and, consequently the turning moment of the bracket 16 about the pivot shaft 20 toward the friction roller 12 can be represented by LF sin 0, where l represents the distance between the axis of the pin 28 and the axis of the pivot shaft 20. Consequently, the holding rollers 13, 14 effectively urge the spindle 11 against the friction roller 12 under a pertinent contacting pressure created by the spring 30, and when it is required to separate the spindle 11 from the friction roller 12, the bracket 16 can be easily turned about the pivot shaft 20 toward a direction opposite to the friction roller 12, by manual operation. To prevent excess turning motion of the bracket away from the friction roller 12, a stopper (not shown) is mounted on the supporting bracket 21.

Next, the operation of the above-mentioned false twisting device is hereinafter illustrated in detail. Referring to FIGS. 1, 2 and 3, when it is required to introduce the yarn 1 into the draw-false twisting apparatus shown in FIG. 1, firstly, the bracket 16 is turned about the pivot shaft 20 so as to move the spindle 11 away from the friction roller 12, then an end of the yarn 1 taken from the package 2 is threaded through the spindle 11. Next the yarn end is sucked into a suction means (not shown). In this condition, the curved surface 26a of the cam plate 26 is forced into contact with the surface of the top portion 19b of the bearing as shown in FIG. 3, by turning the handle 21 manually, and the spindle 11 is supported by the flanges 13a, 13b and 14a, 14b of the holding rollers 13, 14. Thereafter, the bracket 16 is turned toward the friction roller 12 so as to urge the expanded portion 11b of the spindle 11 against the friction roller 12. Then the yarn 1 is introduced to the feed roller 4, a space adjacent to thetwist setting heater 5 and drawing roller 8 successively. During the above-mentioned introducing operation, the passage of the yarn 1 is deviated away from the yarns normal passage upon the heater 5 by means of the guide pin 6, as indicated by a double dot and dash line in FIG. 1. In this condition, the winding means 10 commences to take up the yarn 1. Consequently, the initial false twists are imparted to the yarn by the rotation of the false twisting device 7 which is driven by the frictional contact of the expanded portion 11b of the spindle 11 with the friction roller 12. Next the yarn passage is displaced to normal passage upon the twist setting heater 5 and thereafter the cam plate 26 is manually turned by turning the handle 27 so as to bring the plane portion 26b of the cam plate 26 into contact with the surface of the top portion 19b of the bearing 19 so that the spring 24 is compressed and the bracket 16 is displaced downward to a position represented by a dot and dash line in FIG. 3. According to the abovementioned downward displacement of the bracket 16, the flanges 13b, 14b of the holding rollers l3, 14 are forced to push the head 11a of the spindle 11 downward until the spindle 11 is displaced to a normal running position represented by a dot and dash line in FIG. 3. When the spindle 11 is displaced to the abovementioned normal running position, the thinner portion of the tube 11a of the spindle 11 is forced into contact with the friction roller 12. Consequently, normal false twists are imparted to the yarn 1. As mentioned above, when the yarn is introduced to the drawfalse twisting apparatus, the expanded portion 11b of the spindle 11 contacts the friction roller 11 for a certain length time, and in the normal running condition, the thinner portion of the tube 11a of the spindle 11 is forced into contact with the friction roller 12. Consequently, at the time of introducing the yarn to the drawfalse twisting apparatus, the number of the false twists imparted to the yarnis reduced at a predetermined rate defined by a ratio which equals (the diameter of the thinner portion of the tube 11a)/(the diameter of the expanded portion 11b). According to our tests, it is preferable that the above-mentioned ratio be in a range between 0.5 0.85. If a ratio outside the abovementioned range is applied, it is difficult to attain good results. In the above-mentioned embodiment, the hollow tube member 11a has a laterally expanded portion or step 11b however, the hollow tube member may have a plurality of stepwisely expanded portions or a concave shape. If the shape of the tube 11a of the spindle 11 is changed as mentioned above, the cam profile of the plate cam 26 has to be changed so as to conform with the shape of the spindle tube 11a.

Another embodiment of the false twisting device according to the present invention is shown in FIGS. 5, 6 and 7. In this embodiment, a driven shaft is coaxially mounted to at least one of the holding rollers 13, 14 in such a condition that the driven shaft is forced to contact the friction roller 12, and the false twisting spindle 11 is driven by frictional contact with the holding rollers 13 and 14. To simplify the illustration, only the mechanisms and their functions which are different from the first embodiment shown in FIGS. 1, 2 and 3 are mainly explained hereinafter. The holding rollers l3, 14 are turnably mounted on the bracket 16 and the spindle 11 is turnably held by the holding rollers 13, 14 at the wedge shaped space formed between these rollers l3 and 14 due to the attraction by the permanent magnet 18 as in the first embodiment. In this embodiment, as the spindle 11 is not directly driven by the friction roller 12, it is not necessary to form any stepwisely expanded portions thereon. That is, a driven shaft 31 is coaxially secured to the shaft of the holding roller 13 in such a manner that the driven shaft 31 is extends downwardly from the bracket 16. At the lower end portion of the driven shaft 31, there is provided a coaxially expanded portion 32, and the expanded portion 32 or the main portion of the driven shaft 31 which is above the portion 32 is capable of contacting the friction roller 12 alternately according to the downward or upward displacement of the bracket 16. Consequently, the spindle 11 can be driven at a lower or higher speed according to the above-mentioned displacement of the bracket 16. Referring to FIGS. 6 and 7, a horizontal pin 33 is secured to the upright hollow tube member of the bracket 16 in such a manner that the pin 33 contacts with a cam 34 rigidly mounted on the supporting bracket 21. The cam 34 is provided with a cut-off portion 34b and a cam surface 34a which is capable of contacting the pin 33.

The operation of the false twisting device shown in FIGS. 5, 6 and 7 is as hereinafter illustrated. That is, first, the spindle 11 is separated from the holding rollers 13, 14 after turning the bracket 16 about the pivot shaft 20 away from the friction roller 12. Then an end of the yarn 1 taken from a supply yarn package 1 (see FIG. 1) is threaded into the spindle 11. Thereafter the handle 27 of the plate cam 26 is turned so as to turn the plate cam 26 as shown in FIG. 6, while the yarn is being sucked into a suction means (not shown). In the abovementioned condition, the spindle 11 is held by the auxiliary rollers 13 and 14 by the attraction force of the permanent magnet 18. Thereafter, the bracket 16 is turned toward the friction roller 12 so as to urge the expanded portion 32 of the driven shaft 31 of the auxiliary roller 13 against the friction roller 12. Upon completion of the above-mentioned motion, the yarn 1 is successively introduced to the feed roller 4, the twist setting heater and the drawing roller 8 (see FIG. 1). During the above-mentioned operation, the yarn passage deviates away from the normal passage for carry ing out the normal running operation in response to a displacement of the guide pin 6 as represented by a double dot and dash line shown in FIG. 1. In this condition, the yarn 1 is introduced to the winding means 10. Consequently, the false twists are imparted to the yarn l by the spindle 11 in such a manner that the driven roller 31 is rotated by the frictional contact of the expanded portion 32 thereof with the friction roller 12. In the above-mentioned condition, the pin 33 is maintained at a position where it is not in contact with the cam surface 340 of the cam 34 as shown in FIG. 7. Next, the yarn passage is displaced to the normal passage upon the heater 5 and, thereafter, the plate cam 26 is turned manually so as to bring the plane portion 26b into contact with the surface of the top portion 19b of the bearing 19. According to the above-mentioned turning motion of the plate cam 26, the bearing 19 is displaced downward while compressing the spring 24, and the pin 33 is forced to move downward along the cam surface 34a of the cam 34 so that the bracket 16 is turned about the pivot shaft 20. According to the above-mentioned motion, the expanded portion 32 of the driven shaft 31 is disengaged from the friction roller 12. When the bracket 16 is further displaced downward to the lowermost position thereof, the pin 33 is introduced into the cut off portion 34b of the cam 34. Consequently, the bracket 16 is released from the restriction due to the engagement of the pin 33 with the cam surface 34a which creates the turning motion of the bracket against the spring force of the spring 30. That is, the bracket 16 is again turned about the pivot shaft 20 toward friction roller 12 so that the upper portion of the driven shaft 31 is forced into contact with the friction roller 12.

When the upper portion of the driven shaft 31 is in contact with the friction roller 12, the auxiliary roller 13 is driven at the normal running speed so that normal false twists are imparted to the yarn 1. In the abovementioned embodiment, the upper portion of the driven shaft 31 and the expanded portion 32 are temporarily disengaged from the friction roller 12 at an interval between those intervals of time when they are in contact with the friction roller 12 and, consequently, abrasion of the friction roller 12 and the driven shaft 31 or the expanded portion 32 can be prevented. However, it is also practical to omit the utilization of the above-mentioned pin 33 together with the cam 34 so as to carry out the speed changing operation of the spindle 11 in the same manner as in the first embodiment shown in FIGS. 1, 2 and 3.

Although, in the above-mentioned two embodiments, the relative position of the friction roller 12 to the spindle or the driven shaft of the auxiliary roller 13 is changed by turning the plate cam 26 by means of the handle 27, another means for turning the plate cam 26 may of course, be applied instead of the mechanism of handle 27. However, based on our experience in mill operations, it is our opinion that the handle mechanism shown in the above-mentioned two embodiments is the most practical means for carrying out the speed change operation of the present invention. Still other embodiments of the present inventions are hereinafter illustrated. For the sake of better understanding, elements having similar functions to those shown in FIGS. 3 and 6 are represented by the same reference numerals. Referring to FIGS. 8 and 9, wherein another embodiment of the false twisting device according to the present invention is shown, a pair of holding rollers 13 and 14 are turnably supported by the respective bearings 44 and 45 which are rigidly mounted on an auxiliary horizontal bracket 41 by fastening members 42 and 43, respectively. The permanent magnet 18 is rigidly held by the bracket 41 so that the false twisting spindle 11 is attracted toward the holding rollers 13, 14 so that the tube portion 11a of the spindle 11 rotatably contacts with the upper and lower flanges 13a, 14a and 13b, 14b of the holding rollers 13, 14 in a wedge shaped space between the holding rollers 13, 14 as shown in FIGS. 8 and 9. A hollow cylinder 39 is rigidly mounted on the bracket 16. The bracket 41 is provided with an aperture formed at a position just below the spindle 11 and is turnably mounted on the hollow cylinder 39 in such a way that the hollow cylinder 39 passes through the above-mentioned aperture. Therefore, the auxiliary bracket 41 is capable of turning about a line extended from the longitudinal axis off the spindle 11. To prevent the separation of the bracket 41 from the base bracket 16, a cap member 40 is screwed into the top end portion of the hollow cylinder 39. At the lower end of an extended shaft 35 of the holding roller 13 a follower friction roller 37 is rigidly mounted, while at the lower end of an extended shaft 36 of the holding roller 14, a follower friction roller 38 is rigidly mounted. These shafts 35, 36 are arranged on the auxiliary bracket 41 in such a way that, either one of the follower friction rollers 37, 38 are capable of contact with the friction roller 12. In this embodiment, the diameter of the roller 38 is larger than that of the roller 37. The bracket 41 is provided with a side surface 410, which is a part of a cylindrical surface coaxial to the hollow cylinder 39, and recesses 41b are formed on the side of the surface 41a. A small bracket 46 is rigidly mounted on the bracket 16. The bracket 46 is provided with an aperture 46a and a cap 47 is thread into the aperture 46a. The cap 47 is provided with an aperture 470 and a pin 48 is slidably engaged therein. The pin 48 is provided with laterally expanded portion formed at a free end thereof. A helical expansion spring 49 is inserted into the aperture 46a in such a manner that the pin 48 is always urged toward the side surface 41a of the bracket 41, and the end portion of the pin 48 is capable of being engaged into one of the recesses 41b of the bracket 41 so that the relative position of the bracket 41 to the friction roller 12 can be stably fixed. A pair of grooves 50a, 50b are formed in the bracket 16 so as to permit free turning of the bracket 41 about the hollow cylinder 39. A handle 52 is secured to the bracket 41. Consequently, the relative position of the bracket 41 to the friction roller 12 can be set by operating the handle 52 so as to bring either one of the rollers 37, or 38 into contact with the friction roller 12. When the roller 37 contacts the friction roller 12, the spindle 11 is driven at the normal running speed for carrying out the false twisting operation in a normal manner, while if the operation for threading up the yarn to the apparatus is required, the roller 38 is urged to the friction roller 12 so that the spindle 11 is driven at a slower speed. The mechanism for urging the roller 37 or 38 to the friction roller 12 is similar to the previous embodiment. That is, the pin 28 is secured to the bracket 16 and a hollow cylindrical member 20 is formed at a corner of the bracket 16. The bracket 21 is rigidly mounted on a mechanism frame (not shown) and the horizontal pin 29 is mounted to the bracket 21 so as on project an end of the pin 29 into the bracket 21. The tension spring 30 connects the projected end of the pin 29 and the pin 28. An upright pivot shaft 51 is projects upward from the bracket 21 in such a manner that the hollow cylindrical member 20 is turnably mounted on the pivot shaft 51. A fastening member 53 is threaded into a top portion of the pivot shaft 51. According to the abovementioned construction, during operation the bracket 41 through the base bracket 16 is always forced to turn about the pivot shaft 51 in a direction toward the friction roller 12. Consequently, either one of the rollers 37 or 38 can be urged to the friction roller 12.

As already explained, when it is required to drive the false-twisting spindle 11 in the normal running manner, the handle 52 is operated so as to contact the roller 37 with the friction roller 12, and the stop pin 48 engages with a corresponding recess 41b so that the disposition of the bracket 41 is maintained at the position for normal operation. On the other hand, when threading up of the material yarn into the false twisting apparatus is required, the handle 52 is operated so as to release the contact between the roller 37 and the friction roller 12 and to bring the roller 38 into contact with the friction roller 12. In this condition, the relative position of the bracket 16 to the bracket 41 is maintained stationary by engaging the stop pin 48 with another recess 41b of the bracket 41. Therefore, the operation for changing the driving speed of the spindle 11 can be carried out more easily and stably as compared to the embodiments shown in FIGS. 3 and 6.

As will be understood, the embodiment shown in FIGS. and 11 is a modification of the embodiment shown in FIGS. 8 and 9, because, the only difference is the relative construction of the holding rollers 13 and 14 and the rollers 37 and 38. Therefore, in the following explanation of the false twisting apparatus shown in FIGS. 10 and 11, the explanations related to the elements similar to the elements shown in the embodiment shown in FIGS. 8 and 9, are omitted. Referring to FIGS. 10 and 11, the diameter of the roller 38 is equal to the diameter of the roller 37. However, the diameter of the flange 13a which is identical to the diameter of the flange 13b, is smaller than that of the diameter of the flange 14a which is identical to the diameter of the flange 14b. Therefore, when the roller 37 is urged to the friction roller 12, the spindle 11 is driven at a lower speed then the driving speed due to the contact of the roller 38 with the friction roller 12. As mentioned above, the driving speed of the false twisted spindle 11 can be changed to either from the normal running speed to the slower running speed or from the slower running speed to the normal running speed, by selecting the contact of the friction roller 12 with either one of the rollers 37 and 38. This changing operation is carried out by operating the handle 52.

As mentioned above, in the above-mentioned two embodiments, the mechanism for changing the driving speed of the false twisting spindle 11 is characterized by a pair of holding rollers 13, 14 which have different surface speed for the flanges thereof. In the abovementioned two embodiments, the friction roller 12 is utilized for driving the holding rollers 13, 14 by way of the rollers 37 and 38. However, a friction belt may be utilized instead of the friction roller 12 with the same function.

As mentioned above, with the present invention the number of false twists imparted to the yarn at the time of introducing the filamentary yarn 1 to the draw-false twisting apparatus can be easily reduced in comparison with the normal running condition and the frequent yarn breaks at the time of introducing the yarn to the apparatus can be remarkably reduced, so that the operation of introducing yarn to the apparatus can be effectively, easily carried out. Further, when a yarn is broken at one unit of a false twisting device of an apparatusprovided with a plurality of units, the yarn can be introduced to the unit where the yarn is broken, independently from the other units and, consequently, machine efficiency can be significantly increased. In addition, as the number of false twists imparted to the yarn can be independently changed in any unit, the waste of yarn, which is produced at the time of introducing the yarn to a unit, can be remarkably reduced.

What is claimed is:

1. In a device for imparting false twists on a filamentary yarn, provided with a false twisting spindle provided with a spindle head and a holding means which holds said spindle in rotatable condition and comprises a pair of holding rollers rotatably supported by a bracket in closely facing condition and attraction means for positioning said spindle in a wedge shaped space formed between said holding rollers in such a condition that said spindle is attracted toward said attraction means, said bracket is turnably mounted on a pivot shaft secured to a machine frame, an improvement comprising a driving system related to said false twisting spindle, a frictional driving means being capable of frictionally contacting at least two different portions of said driving system at predetermined different ratios of rotation, means for selectively changing said frictional contact of either one of said portions of said driving system with said frictional driving means under a pressure so that said driving system is driven at said predetermined ratio defined to said portion, means for urging said portion of said driving system to said frictional driving means by turning said bracket about said pivot shaft.

2. An improved device for imparting'false twists on a filamentary yarn according to claim 1, wherein said driving system is a hollow spindle tube formed as one body with said spindle head, said spindle tube is provided with at least one laterally expanded portion formed at an auxiliary middle portion on thereof coaxially, said expanded portion and other portion of said hollow tube are utilized for contacting said frictional driving means.

3. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said driving system is at least one of said holding rollers, said holding roller is provided with a driven shaft projected coaxially downward, a portion of said driven shaft extended below said bracket is provided with a laterally expanded portion formed coaxially thereof, said expanded portion and other portion of said driven shaft below said bracket are utilized for contacting said frictional driving means.

4. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said means for selectively changing said frictional contact of either one of said portions of said driving system is a means for selectively displacing said bracket upward or downward along an axis of said pivot shaft, whereby said driving system is driven at a predetermined speed due to a selective contact of one said contact portions thereof with said frictional driving means.

5. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said driving system comprises said holding rollers having different surface speeds of the flanges thereof, each of the holding rollers is provided with a driven shaft projected coaxially downward, a portion of said driven shaft extended below said bracket is provided with a follower friction roller secured thereto in such a condition that said follower friction roller is capable of being driven by frictional contact with said frictional driving means.

6. An improved device for imparting false twists on a filamentary yarn according to claim 5, wherein said bracket is turnably mounted on a base bracket about a turning axis which coincides with an extended line of a longitudinal axis of said spindle rotatably held by said holding rollers, said means for selectively changing said frictional contact of either one of said portions of said driving system comprises said bracket and said base bracket and a positioning means for selectively fixing the relative portion of said bracket to said base bracket where either one of said follower friction rollers of said holding rollers contacts said frictional driving means.

7. An improved device for imparting false twists on a filamentary yarn according to claim 6, wherein each holding roller is provided with an upper and a lower flange having an identical diameter, but said diameter of flanges of one of the holding rollers is larger than said diameter of flanges of the other holding roller, said follower friction rollers of said holding rollers have an identical diameter.

8. An improved device for imparting false twists on a filamentary yarn according to claim 6, wherein said holding rollers are provided with upper and lower flanges having an identical diameter, said follower friction rollers of said holding rollers have different diameters.

9. An improved device for imparting false twists on a filamentary yarn according to claim I, further comprising means for releasing contact of said driving system with said frictional driving means at an intervened time when said contact of one of said portions of said driving system with said friction means is changed to a contact of the other portion of said driving system with said frictional driving means.

10. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said urging means is a spring means creating a force to turn said bracket about said pivot shaft toward said frictional driving means and said spring means is a helical spring with one end thereof connected to a supporting bracket secured to said machine frame and the other end thereof secured to said bracket in stretched condition.

11. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said frictional driving means is a friction roller.

12. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said frictional driving means is an endless friction belt.

13. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said predetermined ratio of the two different portions of said driving system is in a range between 1 0.5 and l 0.85. 

1. In a device for imparting false twists on a filamentary yarn, provided with a false twisting spindle provided with a spindle head and a holding means which holds said spindle in rotatable condition and comprises a pair of holding rollers rotatably supported by a bracket in closely facing condition and attraction means for positioning said spindle in a wedge shaped space formed between said holding rollers in such a condition that said spindle is attracted toward said attraction means, said bracket is turnably mounted on a pivot shaft secured to a machine frame, an improvement comprising a driving system related to said false twisting spindle, a frictional driving means being capable of frictionally contacting at least two different portions of said driving system at predetermined different ratios of rotation, means for selectively changing said frictional contact of either one of said portions of said driving system with said frictional driving means under a pressure so that said driving system is driven at said predetermined ratio defined to said portion, means for urging said portion of said driving system to said frictional driving means by turning said bracket about said pivot shaft.
 2. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said driving system is a hollow spindle tube formed as one body with said spindle head, said spindle tube is provided with at least one laterally expanded portion formed at an auxiliary middle portion on thereof coaxially, said expanded portion and other portion of said hollow tube are utilized for contacting said frictional driving means.
 3. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said driving system is at least one of said holding rollers, said holding roller is provided with a driven shaft projected coaxially downward, a portion of said driven shaft extended below said bracket is provided with a laterally expanded portion formed coaxially thereof, said expanded portion and other portion of said driven shaft below said bracket are utilized for contacting said frictional driving means.
 4. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said means for selectively changing said frictional contact of either one of said portions of said driving system is a means for selectively displacing said bracket upward or downward along an axis of said pivot shaft, whereby said driving system is driven at a predetermined speed due to a selective contact of one said contact portions thereof with said frictional driving means.
 5. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said driving system comprises said holding rollers having different surface speeds of the flanges thereof, each of the holding rollers is provided with a driven shaft projected coaxially downward, a portion of said driven shaft extended below said bracket is provided with a follower friction roller secured thereto in such a condition that said follower friction roller is capable of being driven by frictional contact with said frictional driving means.
 6. An improved device for imparting false twists on a filamentary yarn according to claim 5, wherein said bracket is turnably mounted on a base bracket about a turning axis which coincides with an extended line of a longitudinal axis of said spindle rotatably held by said holding rollers, said means for selectively changing said frictional contact of either one of said portions of said driving system comprises said bracket and said base bracket and a positioning means for selectively fixing the relative portion of said bracket to said base bracket where either one of said follower friction rollers of said holding rollers contacts said frictional driving means.
 7. An improved device for imparting false twists on a filamentary yarn according to claim 6, wherein each holding roller is provided with an upper and a lower flange having an identical diameter, but said diameter of flanges of one of the holding rollers is larger than said diameter of flanges of the other holding roller, said follower friction rollers of said holding rollers have an identical diameter.
 8. An improved device for imparting false twists on a filamentary yarn according to claim 6, wherein said holding rollers are provided with upper and lower flanges having an identical diameter, said follower friction rollers of said holding rollers have different diameters.
 9. An improved device for imparting false twists on a filamentary yarn according to claIm 1, further comprising means for releasing contact of said driving system with said frictional driving means at an intervened time when said contact of one of said portions of said driving system with said friction means is changed to a contact of the other portion of said driving system with said frictional driving means.
 10. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said urging means is a spring means creating a force to turn said bracket about said pivot shaft toward said frictional driving means and said spring means is a helical spring with one end thereof connected to a supporting bracket secured to said machine frame and the other end thereof secured to said bracket in stretched condition.
 11. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said frictional driving means is a friction roller.
 12. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said frictional driving means is an endless friction belt.
 13. An improved device for imparting false twists on a filamentary yarn according to claim 1, wherein said predetermined ratio of the two different portions of said driving system is in a range between 1 : 0.5 and 1 : 0.85. 